Camping in sub freezing weather

Consider taking one extra cylinder of propane. When you get back from skiing and the indicator just then says you are on the reserve at 6pm and the propane supply is closed for the day can make for a worrisome evening. Don't ask how I know.

I would stow the fresh water hose overnight. Just bring it out to fill the fresh holding tank.

If chains are appropriate consider at least one set of those flimsy cable chains for the trailer.